Halogen-Modified Lithium Phosphorus Sulfide Solid Electrolyte

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Solution Overview

Problem

Conventional sulfide-based solid electrolytes for all-solid batteries are prone to hydrolysis, especially in high dew point environments, leading to reduced ionic conductivity and limited application scope.

Innovation Solution

A solid electrolyte comprising lithium, phosphorous, sulfur, and bromine, with specific peak conditions in the 31P-NMR spectrum, which enhances hydrolysis resistance and maintains high ionic conductivity, is developed. The electrolyte has a peak in the 75.0-80.0 ppm range and an intensity ratio of 0.5 or less, ensuring minimal hydrolysis and high conductivity.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If conventional sulfide-based solid electrolyte materials are used, then high ionic conductivity can be achieved, but the materials are easily hydrolyzed in high dew point environments

Engineering Contradiction:
Improvehydrolysis resistanceVSAvoidhydrolysis in high dew point environment
Core Design Contradiction:
ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The invention changes the chemical composition parameters of the solid electrolyte by incorporating specific halogen elements (Cl, Br, or I) into the Li-P-S system. The halogen content is controlled within specific ranges (0.1-5 mol%, preferably 0.5-3 mol%) to optimize both hydrolysis resistance and ionic conductivity. This compositional parameter change fundamentally alters the material's chemical stability without sacrificing its ionic conduction capability.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The invention creates a composite solid electrolyte material by combining conventional Li-P-S components with halogen-containing compounds. The composite structure integrates the high ionic conductivity of Li-P-S with the enhanced hydrolysis resistance provided by halogen elements, achieving synergistic effects that resolve the contradiction between conductivity and stability.

Inventive Principle:
Principle #40Composite materials

Data Source

PatentEP3361545B1Solid electrolyte
Publication Date: 2020.06.24 IDEMITSU KOSAN CO LTD
  • EP3361545B1 patent drawingFigure 1~2
  • EP3361545B1 patent drawingFigure 3~4
  • EP3361545B1 patent drawingFigure 5

AI summary

A solid electrolyte including an alkali metal element, phosphorous, sulfur and halogen as constituent components.